Feature: add obsidian commands for user scripts

[willasm]

Assigns Obsidian commands for specified user scripts. I needed this as my collection of JS scripts for JS Engine keeps growing and having to pick a script from the growing list presented by the command JS Engine: Execute JS File is becoming awkward. I also wanted to be able to assign hotkeys to frequently used scripts.

Added instructions on usage to README.md (Under heading Create Obsidian commands for user scripts)

Here are some pictures to show exactly what it adds...

Command Palette

Settings with 2 scripts added

Settings with script selection dropdown

Thanks for the great plugins! Getting a lot of use from this and Meta Bind as well, William.